In the medical field, injection sites usable with pointed cannula have long been known. For example, such sites can be formed with a housing having a fluid flow path therein. A septum is positioned in the housing closing the fluid flow path.
One injection site usable with a piercing cannula is disclosed in U.S. Pat. No. 4,412,573 to Zdeb entitled "Injection Site." The Zdeb patent is assigned to Assignee of the present invention.
The pointed cannula can be forced through the septum into fluid flow communication with the flow path in the housing. Known injection sites usable with a piercing cannula can be physically damaged by repetitive piercing caused by the sharp cannula. This damage, known as coring or laceration, can result in subsequent leakage.
For example, standard drug vials which have rubber stoppers or sites, are routinely entered with a conventional hypodermic needle. From repeated entry of the needle, the stopper may leak as a result of the coring and no longer function as a sterile barrier. Particulate matter can subsequently be generated and injected into the patient or otherwise contaminate the content of the vial. These problems are magnified with vials which are accessed multiple times.
Due to problems associated with infectious agents, personnel using such pointed cannulae do so with great care. Notwithstanding careful and prudent practice, from time to time, accidents do occur and individuals using such pointed cannulae jab themselves.
In an effort to overcome some of these difficulties, devices known as "dispensing pins" can be used to penetrate the site or stopper of multiple dose vials. Such dispensing pins are typically a sharp spike cannula and can employ a check valve in an effort to prevent gross fluid leakage. On the opposing end of the cannula is a standard luer fitment typically closed off, when not in use, by a cap. These dispensing pins tend to disengage from the vial stopper so that some leakage still occurs. Further, it is difficult to maintain sterile conditions on this multiple dose system.
Injection sites usable with a blunt cannula are also known. For example, U.S. Pat. No. 4,197,848 issued to Garrett et al. entitled "Closed Urinary Irrigation Site" and assigned to the assignee of the present invention discloses one such injection site. That injection site is a relatively low pressure device having a relatively thin, molded, sealing member. The sealing member has an opening therethrough.
A blunt cannula can be forced through the sealing member placing the cannula into fluid flow communication with a fluid flow pathway in the injection site.
Injection sites of the type noted above usable with a blunt cannula have the advantage that the blunt cannula will not pierce the skin of a user. On the other hand, it is important that the pre-slit injection site reseal with enough force that fluids do not ooze therefrom and that airborne particulate matter, bacterial or viral matter do not enter therethrough.
Hence, there continues to be a need for a pre-slit injection site which can be used with a variety of solutions and over a range of fluid pressures. Further, there continues to be a need for such a pre-slit injection site which will reliably reseal even after many insertions of the blunt cannula.
Such an injection site should be able to receive a large number of insertions of the cannula without displaying reseal failure. Such an injection site should provide for improved alignment of the cannula on insertion. Improved alignment will result in less chance of damage to the injection site after repeated insertions of the cannula. Preferably, the injection site would also be usable with a pointed cannula. Preferably, a pre-slit injection site usable with a blunt cannula will provide a reasonable level of insertion force such that health care personnel will readily be able to insert the blunt cannula, yet the cannula will not easily fall from or drop out of contact with the septum.